Micromachined structures made by combined wet and dry etching

ABSTRACT

Novel micromachined structures made by combined wet and dry etching.

RELATED APPLICATIONS

[0001] The present application claims the benefit of priority from copending provisional patent applications No. 60/269,011 filed on Feb. 14, 2001 and No. 60/269,010 and which are hereby incorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to micromachining. More particularly, the present invention relates to a new method for combining directional ion etching and anisotropic wet etching. The present invention is particularly applicable to silicon micromachining.

BACKGROUND OF THE INVENTION

[0003] Silicon optical bench chips often have anisotropically etched Grooves for holding optical fibers or other components. Also, SiOB chips can have dicing saw cuts that function as fiber stops, thereby providing passive longitudinal alignment for an optical fiber. Such optical bench chips are well known in the art.

[0004] In some cases, it is not desirable or practical to have dicing saw cuts. Particularly, dicing saw cuts can be undesirable because they typically must extend across an entire wafer.

[0005] It would be an advance in the art to provide fiber stops in optical bench chips without requiring dicing saw cuts.

[0006] Also, it would be an advance in the art of micromachining to provide a wider array of precision-made structures. Particularly, it would be advance to combine multiple micromachining techniques to provide unusual, useful structures.

DETAILED DESCRIPTION

[0007] The present invention provides novel micromachined structures made by combined wet/dry etching. The structures can be used in a variety of micromachined devices, including microoptical submounts and the like.

[0008] It will be clear to one skilled in the art that the above embodiment may be altered in many ways without departing from the scope of the invention. Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents. 

What is claimed is:
 1. A micromachined structure comprising: a) a first wet etched pit having a first flat surface; b) a second wet etched pit having a second flat surface; c) a dry pit disposed between the first flat surface and second flat surface.
 2. The micromachined structure of claim 1 wherein the structure is made of <100>silicon.
 3. The micromachined structure of claim 1 wherein the wet etched pits are anisotropically wet etched pits.
 4. A micromachined structure comprising: a) a wet etched pit having a flat surface; b) a ring-shaped dry pit disposed in the wet etched pit; c) a second wet etched pit disposed in the ring-shaped dry pit, wherein the second wet etched pit extends above the flat surface
 5. The micromachined structure of claim 4 wherein the structure is made of <100>silicon.
 6. The micromachined structure of claim 4 wherein the wet etched pits are anisotropically wet etched pits.
 7. A micromachined structure comprising: a) a wet etched pit having a flat surface; b) a U-shaped dry pit disposed in the wet etched pit; c) a wedge disposed in the U-shaped dry pit, wherein the wedge extends above the flat surface.
 8. The micromachined structure of claim 7 wherein the structure is made of <100>silicon.
 9. The micromachined structure of claim 7 wherein the wet etched pits are anisotropically wet etched pits.
 10. A micromachined substrate comprising: a) a wet etched pit; b) a dry-etched hole disposed in the wet etched pit, wherein the dry hole extends through the substrate.
 11. The micromachined substrate of claim 10 wherein the structure is made of <100>silicon.
 12. The micromachined substrate of claim 10 wherein the wet etched pits are anisotropically wet etched pits.
 13. The micromachined substrate of claim 10 wherein the dry hole is centered in the wet pit.
 14. The micromachined substrate of claim 10 further comprising an optical fiber disposed in the dry hole. 